Spindle motor having spindle motor stator with laminate layers for increased head stack assembly access

ABSTRACT

A spindle motor for use in a disk drive having a rotatable head stack assembly. The spindle motor has a spindle motor hub. The spindle motor further has a magnet radially attached about the spindle motor hub. The spindle motor further has a spindle motor stator. The spindle motor has a stator rim. The spindle motor stator further has a plurality of stator teeth arrayed about and internally extending from the stator rim. The stator teeth are sized to fit about the magnet in operable communication therewith for rotating the spindle motor hub. The stator teeth have laminate layers. The stator teeth have a least one reduced height stator tooth having fewer laminate layers than a remainder of the stator teeth. The reduced height stator tooth is positionable adjacent the head stack assembly for allowing the head stack assembly to pivot over the reduced height stator tooth.

CROSS-REFERENCE TO RELATED APPLICATION

Not Applicable.

This application is a division of application Ser. No. 09/846,078 filedApr. 3, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to spindle motors for use indisk drives, and more particularly to a spindle motor having a spindlemotor stator with laminate layers for increased head stack assemblyaccess.

2. Description of the Prior Art

The typical hard disk drive includes a disk drive base, and a head diskassembly (HDA) and a printed circuit board assembly (PCBA) attached tothe disk drive base. The head disk assembly includes at least onemagnetic disk, a spindle motor for rotating the disk, and a head stackassembly (HSA) that includes at least one transducer head, typicallyseveral, for reading and writing data to and from the disk. The printedcircuit board assembly includes a servo control system in the form of adisk controller for generating servo control signals. The head stackassembly is controllably positioned in response to the generated servocontrol signals from the disk controller. In so doing, the attachedheads are moved relative to tracks disposed upon the disk.

The head stack assembly includes an actuator assembly, at least one headgimbal assembly, and a flex circuit cable assembly. A conventional“rotary” or “swing-type” actuator assembly typically comprises anactuator body that rotates on a pivot assembly between limitedpositions, a coil portion that extends from one side of the actuatorbody to interact with one or more permanent magnets to form a voice coilmotor, and one or more actuator arms which that extend from an oppositeside of the actuator body. A head gimbal assembly includes at least onetransducer head, sometimes two, which is distally attached to each ofthe actuator arms. The actuator assembly includes the actuator body thathas a bore and a pivot bearing cartridge engaged within the bore. The atleast one head gimbal assembly and the flex circuit cable assembly areattached to the actuator assembly.

The spindle motor includes a hub that is rotatably attached to the diskdrive base. The hub has an outer flange that supports one of the disks.Additional disks may be stacked and separated with spacers. The spindlemotor further includes an annular magnet and a spindle motor stator.Where space efficiency is of vital concern, the magnet is typicallyattached about the lowermost portion of the hub below the flange. Themagnet consists of a predetermined number of N and S poles that aredisposed alternately circumferentially about the magnet. The spindlemotor stator includes an outer rim that is attached to the disk drivebase and a plurality of internally facing stator teeth. The stator teethare equally spaced and extend from the stator rim. The spindle motorstator is sized to fit about the hub and in particular the magnet. Eachstator tooth includes windings which selectively conduct current tocreate a magnetic field that interacts with the various poles of themagnet. Such interaction results in forces applied to the hub which tendto rotate the hub. In those disk drives capable of reading both sides ofthe disks, the head stack assembly includes an actuator arm that extendsand pivots between the vertical region between the lowermost disk andthe spindle motor stator. A magnetic shield is provided between the headstack assembly in such region over the stator teeth for protectingagainst magnetic flux interacting with the magnetic data on the disk andthe head stack assembly.

A topic of concern is the desire to reduce the overall disk drive size.Such disk drives may have a variety of applications such as in hand heldor portable electronic devices. The exterior size and shape of the diskdrive is often referred to as a “form factor”. Reduction of such diskdrive form factor has proven challenging. This is because the merereduction of the size of the various disk drive components may result insuch components being unable to conform to required specifications andstandard form factors for such components, and may result ininstallation or assembly difficulties.

One particular area of focus is the reduction of the height of the diskdrive. As mentioned above, a prior art arrangement includes a loweractuator arm which extends and pivots between the vertical regionbetween the lowermost disk and the spindle motor stator. Such priorarrangement is contemplated to be a limited factor in the overall sizingof the disk drive height. Accordingly, there is a need in the art for animproved spindle motor configuration in comparison to the prior art.

SUMMARY OF THE INVENTION

An aspect of the invention can be regarded as a spindle motor for use ina disk drive having a rotatable head stack assembly. The spindle motorhas a spindle motor hub. The spindle motor further has a magnet radiallyattached about the spindle motor hub. The spindle motor further has aspindle motor stator. The spindle motor stator has a stator rim. Thespindle motor stator further has a plurality of stator teeth arrayedabout and internally extending from the stator rim. The stator teeth aresized to fit about the magnet in operable communication therewith forrotating the spindle motor hub. The stator teeth have laminate layers.The stator teeth have at least one reduced height stator tooth. Thereduced height stator tooth has fewer laminate layers than a remainderof the stator teeth. The reduced height stator tooth is positionableadjacent the head stack assembly for allowing the head stack assembly topivot over the reduced height stator tooth.

The reduced height stator tooth may have a width greater than aremainder of the stator teeth. The reduced height stator tooth may havea tooth body portion and a distal shoe extending from the tooth bodyportion. The shoe is disposed adjacent the magnet. Further, the distalshoe may extend vertically beyond the tooth body portion.

According to another aspect of the present invention, there is provideda spindle motor for use in a disk drive having a rotatable head stackassembly. The spindle motor has a spindle motor hub. The spindle motorfurther has a magnet radially attached about the spindle motor hub. Thespindle motor further has a spindle motor stator. The spindle motorstator has a stator rim formed of at least two vertically stacked statorrim laminate layers. The spindle motor stator further has a plurality ofstator teeth arrayed about and internally extending from the stator rim.The stator teeth are sized to fit about the magnet in operablecommunication therewith for rotating the spindle motor hub. The statorteeth are each formed of at least two stator tooth laminate layers. Thestator tooth laminate layers are respectively attached to the stator rimlaminate layers. The spindle motor stator further has at least onereduced height stator tooth having at least two reduced height statortooth laminate layers horizontally off-set from and vertically formedtowards each other. The reduced height stator tooth being is adjacentthe head stack assembly for allowing the head stack assembly to pivotover the reduced height stator tooth.

In addition, the at least two reduced height stator tooth laminatelayers may include an upper laminate layer and a lower laminate layer.The upper and lower laminate layers may be horizontally off-set fromeach other. In another embodiment, the at least one reduced heightstator tooth laminate layers include an upper laminate layer, a lowerlaminate layer, and an inner laminate layer between the upper and lowerlaminate layers. The upper and lower laminate layers are horizontallyoff-set from the inner laminate layer. According to another embodiment,the at least two reduced height stator tooth laminate layers include anupper laminate layer and a lower laminate layer. The lower laminatelayer extends horizontally from the stator rim and the upper laminatelayer is formed towards the lower laminate layer. Further, in anotherembodiment of the stator motor, all of the stator teeth may take theform of the above described reduced height stator tooth.

According to another aspect of the present invention, there is provideda spindle motor for use in a disk drive having a rotatable head stackassembly. The spindle motor has a spindle motor hub. The spindle motorfurther has a magnet radially attached about the spindle motor hub. Thespindle motor further has a spindle motor stator. The spindle motorstator has a stator rim formed of at least two vertically stacked statorrim laminate layers. The spindle motor stator further has a plurality ofstator teeth arrayed about and internally extending from the stator rim.The stator teeth are sized to fit about the magnet in operablecommunication therewith for rotating the spindle motor hub. The statorteeth have laminate layers formed to a first thickness. The stator teethhave at least one reduced height stator tooth. The reduced height statortooth has laminate layers formed to a second thickness less than thefirst thickness. The reduced height stator tooth is positionableadjacent the head stack assembly for allowing the head stack assembly topivot over the reduced height stator tooth. Further, the reduced heightstator tooth may have a width greater than a remainder of the statorteeth.

In additional embodiments of the present invention, there are provideddisk drives each having a disk drive base and a head stack assembly. Theabove-mentioned stator motors may be included the disk drives.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a disk drive including aspindle motor as constructed in accordance with an aspect of the presentinvention;

FIG. 2 is a top view of a spindle motor in relation to a portion of thehead stack assembly;

FIG. 3 is a cross sectional view of the disk drive including the spindlemotor as seen along axis 3—3 of FIG. 2;

FIG. 4 is a cross sectional view of a stator tooth as seen along axis4—4 of FIG. 2;

FIG. 5 is a cross sectional view of a reduced height stator tooth asseen along axis 5—5 of FIG. 2;

FIG. 6 is top view of the reduced height stator tooth of FIG. 5;

FIG. 7 is a top view of a reduced height stator tooth having anincreased width according to another aspect of the present invention;

FIG. 8 is a top view of a spindle motor as including the reduced heightstator tooth of FIG. 7;

FIG. 9 a top view of a reduced height stator tooth having horizontallyoff-set laminate layers according to another aspect of the presentinvention;

FIG. 10 is a side view of the reduced height stator tooth as seen alongaxis 10—10 of FIG. 9;

FIG. 11 is a side view of the reduced height stator tooth as seen alongaxis 11—11 of FIG. 9;

FIG. 12 a top view of a reduced height stator tooth having horizontallyoff-set laminate layers according to another aspect of the presentinvention;

FIG. 13 is a side view of the reduced height stator tooth as seen alongaxis 13—13 of FIG. 12;

FIG. 14 is a side view of the reduced height stator tooth as seen alongaxis 14—14 of FIG. 12;

FIG. 15 is a side view of a reduced height stator tooth havinghorizontally off-set laminate layers the lower layers of which extendinghorizontally according to another aspect of the present invention;

FIG. 16 is an opposing side view of the reduced height stator tooth ofFIG. 15;

FIG. 17 is a reduced height stator tooth having a reduced heightlaminate layers according to another aspect of the present invention;and

FIG. 18 is an opposing side view of the reduced height stator tooth ofFIG. 17.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings wherein the showings are for purposes ofillustrating preferred embodiments of the present invention only, andnot for purposes of limiting the same, FIGS. 1-18 illustrate a diskdrive 10 in accordance with the aspects of the present invention.

Referring now to FIG. 1 there is depicted an exploded perspective view adisk drive 10 constructed in accordance with an aspect of the presentinvention. The disk drive 10 includes a head disk assembly (HDA) 12 anda printed circuit board assembly (PCBA) 14. The head disk assembly 12includes a disk drive base 16 and a cover 18 that collectively house atleast one magnetic disk 20 (although single disk 20 is shown, multipledisks 20 may be included). The disk 20 contains a plurality of tracks 22for reading and writing data. The head disk assembly 12 further includesa spindle motor 24 (such as shown in FIG. 2) for rotating the disk 20and a head stack assembly 26. A pivot cartridge 28 is provided forpivoting the head stack assembly 26 relative to the rotating disk 20 forreading and writing data to and from the disk 20.

Referring additionally to FIGS. 2-5, the spindle motor 24 includes aspindle motor hub 30 and an annular magnet 32 disposed about the hub 30.The hub 30 has an annular flange 34 is configured to support the disk20. The spindle motor 24 further includes a spindle motor stator 36(such as shown in FIG. 2) that interacts with the magnet 32 for rotatingthe spindle motor hub 30 and attached disk 20. Over the spindle motorstator 36, a horizontally disposed magnetic shield 38 is provided whichshields the disk 20 and the head stack assembly 26 from magnetic fluxgenerated by the interaction of the magnet 32 and the spindle motorstator 36.

Referring specifically to FIG. 2, there is depicted a top view of thespindle motor 24 according to an aspect of the present invention. Inaddition, a portion of the head stack assembly 26 is depicted inrelation to the spindle motor 24. In order to observe the spindle motorstator 34, the horizontally disposed magnetic shield 38 is not depictedin this view of FIG. 2.

The spindle motor hub 30 has an axis of rotation 40. The spindle motorstator 24 has a stator rim 42 and a plurality of stator teeth 44 arrayedabout and internally extending from the stator rim 42 towards the axisof rotation 40. The stator teeth 44 are sized to fit about the magnet 32in operable communication therewith for rotating the spindle motor hub30.

The stator teeth 44 have laminate layers 46 (denoted 46 a-d), as furtherdescribed below. The stator teeth 44 have at least one reduced heightstator tooth 48 (two are shown in FIG. 2). The at least one reducedheight stator tooth 48 having fewer laminate layers 58 (denoted 58 c-d)than a remainder of the stator teeth 44, as further described below. Theat least one reduced height stator tooth 48 is positionable adjacent thehead stack assembly 26 for allowing the head stack assembly 26 to pivotover the reduced height stator tooth 48.

The spindle motor stator 36 of this embodiment allows the head stackassembly 26 to be effectively translated downward in comparison to priorart stator arrangements which require the stator teeth to have the samenumber of laminate layers thereof, and therefore the same height. To theextent that the vertical positioning of the head stack assembly 26 is alimiting factor in the overall height form factor of the disk drive 10,such effective translation directly results in facilitating reduction ofsuch overall height form factor.

Referring specifically to FIG. 3, there is depicted a cross sectionalview of the disk drive 10 including the spindle motor 24 of FIG. 2 asseen along axis 3—3. A stator base 50 may be included having a steppedportion 52 sized and configured to seat the stator rim 42. The statorbase 50 is attached to the disk drive base 16. It is contemplated thatthe stator base 50 may be integrally formed with the disk drive base 16.The spindle motor hub 30 is configured to rotate in relation to thestator base 50. In this regard, in one configuration, an annular member54 may extend from stator base 50. Bearing sets 56 may be provided whichare mounted within the spindle motor hub 30 in communication with theannular member 54 for facilitating rotation of the hub 30.

Referring now to FIG. 4, there is depicted a cross sectional view of oneof the stator teeth 44, as seen along axis 4—4 of FIG. 2. The statortooth 44 is representative of a remainder of the stator teeth 44. Inthis regard, each of the stator teeth 44 includes windings 58thereabout. The windings 58 of each of the stator teeth 44 selectivelyconduct current to create a magnetic field that interacts with variouspoles of the magnet 32. Such interaction results in forces applied tothe spindle motor hub 30 which tend to rotate the spindle motor hub 30.The windings 58 have a total vertical height H.

The each of the stator teeth 44 may have a tooth body portion 62extending from the stator rim 42 and a distal shoe 64 extending from thetooth body portion 62. As mentioned above, the stator teeth 44 includelaminate layers 46 a-d (at least two are required). In this regard, thelaminate layers 46 a-d form the tooth body portion 62. Further, thedistal shoe 64 may be formed of laminate layers 66 a-d. Such laminatelayers 66 a-d are aligned with the laminate layers 46 a-d and may beintegrally formed with the same. Further the stator rim 42 may be formedof may be formed of laminate layers 68 a-d. Such laminate layers 68 a-dare aligned with the laminate layers 46 a-d and may be integrally formedwith the same.

The stator rim 42 may include a reduced height segment 70. The reducedheight segment 70 may be formed of laminate layers 72 c-d which arealigned with laminate layers 68 c-d. Referring additionally to FIG. 5,there is depicted a cross sectional view of the reduced height statortooth 48 as seen along axis 5—5 of FIG. 2. FIG. 6 is a top view of thereduced height stator tooth 48 of FIG. 5. Each reduced height statortooth 48 may have a tooth body portion 74 extending from the reducedheight segment 70 and a distal shoe 76 extending from the tooth bodyportion 74. The distal shoe 76 is disposed adjacent the magnet 32. Thelaminate layers 72 c-d form the tooth body portion 74. The distal shoe76 may be formed of laminate layers 78 c-d. Such laminate layers 78 c-dare aligned with the laminate layers 72 c-d and may be integrally formedwith the same. Windings 80 are formed about the tooth body portion 74.Further, the distal shoe 76 may extend vertically beyond the tooth bodyportion 74.

It is contemplated that the motor torque constant of the spindle motor24 is a function of the number of stator teeth 44, flux density througheach of the stator teeth 44, the number of windings 64 about each statortooth 44, and the radial distance between the stator tooth 44 and themagnet 30. In this regard, the flux density through each of the statorteeth 44 is a function of the surface area of portion of the statortooth 44 adjacent the magnet 30. In this regard, so as to increase sucharea, the laminate layers 78 c-d of the distal shoe 76 may eachrespectively have a height greater than a height of the laminate layers58 c-d of the tooth body portion 74.

Referring now to FIGS. 7 and 8, there is depicted another embodiment ofa spindle motor stator 82. The spindle motor 82 is similar to the abovedescribed spindle motor 24, however the reduced height stator teeth 48are replace with a reduced height stator tooth 86. In this regard, thespindle motor 82 includes stator teeth 84 and a stator rim 86 similar tothe above described stator teeth 44 and the stator rim 42. Further, thestator rim 86 includes a reduced height segment 90 similar to thereduced height segment 70. The reduced height stator tooth 88 is similarin configuration to the reduced height stator tooth 48, however, thereduced height stator tooth 48 has a tooth body portion 92 having awidth (W) greater than a remainder of the stator teeth 44. In thisregard, the cross sectional area through which magnetic flux may flow isrelatively increased.

Referring now to FIGS. 9-11, there is depicted another embodiment of areduced height stator tooth 94 which may be incorporated into a spindlemotor similar in other respects to the spindle motor 24. The reducedheight stator tooth 94 extends from a stator rim 96 similar to thestator rim 42. Multiple reduced height stator teeth 94 may be utilized.The reduced height stator tooth 94 has at least two reduced heightstator tooth laminate layers (such as 98 a and 98 b, 98 a and 98 c, 98 band 98 d, 98 c and 98 d) horizontally off-set from and vertically formedtowards each other. As depicted, four reduced height stator toothlaminate layers 98 a-d are provided. The reduced height stator tooth 94is positionable adjacent the head stack assembly 26 for allowing thehead stack assembly 26 to pivot over the reduced height stator tooth 94.The reduced height stator tooth laminate layer 98 a is an upper laminatelayer, the reduced height stator tooth laminate layer 98 d is a lowerlaminate layer, and the reduced height stator tooth laminate layers 98b-c are inner laminate layers which are interposed between the upper andlower laminate layers. As can be seen, the reduced height stator toothlaminate layers 98 a, 98 d are horizontally off-set from the reducedheight stator tooth laminate layers 98 b-c. Further, the reduced heightstator tooth laminate layers 98 a, 98 d are formed towards each other.As such, as used herein, the language, formed towards each other, refersto at least one of the laminate layers being formed towards anotherlaminate layer. Thus, laminate layer 98 a is considered to be formedtowards laminate layers 98 b-d. The reduced height stator tooth 94includes a tooth body portion 100 and distal shoe 102. The tooth bodyportion 100 is formed of the laminate layers 98 a-d. Windings 104 areformed about the tooth body portion 100. The distal shoe 102 is formedof laminate layers 106 a-d which are attached to and may be integrallyformed with laminate layers 98 a-d. The stator rim 96 is formed oflaminate layers 108 a-d which are attached to and may be integrallyformed with laminate layers 98 a-d

Referring now to FIGS. 12-14, there is depicted another embodiment of areduced height stator tooth 110 which may be incorporated into a spindlemotor similar in other respects to the spindle motor 24. The reducedheight stator tooth 110 extends from a stator rim 112 similar to thestator rim 42. Multiple reduced height stator teeth 110 may be utilized.The reduced height stator tooth 110 has at least two reduced heightstator tooth laminate layers (such as 114 a and 114 c, 114 a and 114 d,114 b and 114 c, 114 b and 114 d) horizontally off-set from andvertically formed towards each other. As depicted, four reduced heightstator tooth laminate layers 114 a-d are provided. The reduced heightstator tooth 110 is positionable adjacent the head stack assembly 26 forallowing the head stack assembly 26 to pivot over the reduced heightstator tooth 110. The reduced height stator tooth laminate layer 114 ais an upper laminate layer, the reduced height stator tooth laminatelayer 114 d is a lower laminate layer, and the reduced height statortooth laminate layers 114 b-c are inner laminate layers which areinterposed between the upper and lower laminate layers. As can be seen,the reduced height stator tooth laminate layers 114 a-b are horizontallyoff-set from the reduced height stator tooth laminate layers 114 c-d.Further, the reduced height stator tooth laminate layers 114 a, 114 dare formed towards each other. The reduced height stator tooth 110includes a tooth body portion 116 and distal shoe 118. The tooth bodyportion 116 is formed of the laminate layers 114 a-d. Windings 120 areformed about the tooth body portion 116. The distal shoe 118 is formedof laminate layers 122 a-d which are attached to and may be integrallyformed with laminate layers 114 a-d. The stator rim 112 is formed oflaminate layers 1124 a-d which are attached to and may be integrallyformed with laminate layers 114 a-d

Referring now to FIGS. 15-16, there is depicted another embodiment of areduced height stator tooth 126 which may be incorporated into a spindlemotor similar in other respects to the spindle motor 24. The reducedheight stator tooth 126 extends from a stator rim 128 similar to thestator rim 42. Multiple reduced height stator teeth 126 may be utilized.The reduced height stator tooth 126 is formed of reduced height statortooth laminate layers 130 a-d. The reduced height stator tooth 126 issimilar in configuration to the reduced height stator tooth 126,however, laminate layers 130 c-d are formed to extend horizontally fromthe stator rim 128. The reduced height stator tooth 126 is positionableadjacent the head stack assembly 26 for allowing the head stack assembly26 to pivot over the reduced height stator tooth 126. The reduced heightstator tooth laminate layer 130 a is an upper laminate layer, thereduced height stator tooth laminate layer 130 d is a lower laminatelayer, and the reduced height stator tooth laminate layers 130 b-c areinner laminate layers which are interposed between the upper and lowerlaminate layers. As can be seen, the reduced height stator toothlaminate layers 130 a-b are horizontally off-set from the reduced heightstator tooth laminate layers 130 c-d. Further, the reduced height statortooth laminate layers 130 a, 130 d are formed towards each other. Assuch, as used herein, the language, formed towards each other, refers toat least one of the laminate layers being formed towards anotherlaminate layer. Thus, laminate layer 130 a is considered to be formedtowards laminate layers 130 c-d. The reduced height stator tooth 126includes a tooth body portion 132 and distal shoe 134. Windings 136 areformed about the tooth body portion 132. As such, in comparison thereduced height stator tooth 110, the configuration of the presentreduced height stator tooth 126 facilitates the head stack assembly 26to be more closely positioned adjacent the reduced height stator tooth126.

In another embodiment of the spindle motor stator 24, all of the statorteeth 44 may take the form of the above described reduced height statortooth 126.

Referring now to FIGS. 17-18, there is depicted another embodiment of areduced height stator tooth 138 which may be incorporated into a spindlemotor similar in other respects to the spindle motor 24. The reducedheight stator tooth 138 extends from a stator rim 140 similar to thestator rim 42. Multiple reduced height stator teeth 138 may be utilized.The reduced height stator tooth 138 is formed of reduced height statortooth laminate layers 142 a-d. The reduced height stator tooth 138 issimilar in configuration to the stator teeth 44, however, laminatelayers 142 a-d are formed to a thickness less than a thickness of thestator teeth 44. The reduced height stator tooth 138 is positionableadjacent the head stack assembly 26 for allowing the head stack assembly26 to pivot over the reduced height stator tooth 138. Because of suchrelatively lessened thickness, the configuration of the present reducedheight stator tooth 138 facilitates the head stack assembly 26 to bemore closely positioned adjacent the reduced height stator tooth 138.The reduced height stator tooth 138 includes a tooth body portion 144and distal shoe 146. Windings 152 are formed about the tooth bodyportion 144. The stator rim 140 is formed of laminate layers 148 whichare attached to and may be integrally formed with laminate layers 142a-d. Further, the distal shoe 146 is formed of laminate layers 150 a-d.It is contemplated that the stator rim 140, tooth body portion 144 anddistal shoe 146 may be initially formed to be of a similar thickness orheight. Subsequently, the tooth body portion 144 may undergo a formingprocess to achieve such relatively reduced thickness. In addition, it iscontemplated that the width of the tooth body portion 144 may be greaterthan the width of the stator teeth 44.

In another embodiment of the spindle motor stator 24, all of the statorteeth 44 may take the form of the above described reduced height statortooth 138.

We claim:
 1. A spindle motor for use in a disk drive having a rotatablehead stack assembly, the spindle motor comprising: a spindle motor hubdefining an axis of rotation; a magnet radially attached about thespindle motor hub; and a spindle motor stator including: a stator rim; aplurality of stator teeth extending from the stator rim, the statorteeth being sized to fit about the magnet in operable communicationtherewith for rotating the spindle motor hub, each of the stator teethhaving a tooth body portion attached to the stator rim and a distal shoeadjacent the magnet, the tooth body portion and the distal shoe having asame vertical height in a direction along the axis of rotation; and atleast one reduced height stator tooth extending from the stator rim, thereduced height stator tooth being sized to fit about the magnet inoperable communication therewith for rotating the spindle motor hub,reduced height the stator tooth having a tooth body portion attached tothe stator rim and a distal shoe adjacent the magnet, the distal shoeextends vertically beyond the tooth body portion in a direction alongthe axis of rotation, only the at least one reduced height stator toothbeing positionable adjacent the head stack assembly for allowing thehead stack assembly to pivot over the reduced height stator tooth.
 2. Adisk drive comprising: a disk drive base; a head stack assemblyrotatably attached to the disk drive base; and a spindle motor attachedto the disk drive base including: a spindle motor hub defining an axisof rotation; a magnet radially attached about the spindle motor hub; anda spindle motor stator including: a stator rim; a plurality of statorteeth extending from the stator rim, the stator teeth being sized to fitabout the magnet in operable communication therewith for rotating thespindle motor hub, each of the stator teeth having a tooth body portionattached to the stator rim and a distal shoe adjacent the magnet, thetooth body portion and the distal shoe having a same vertical height ina direction along the axis of rotation; and at least one reduced heightstator tooth extending from the stator rim, the reduced height statortooth being sized to fit about the magnet in operable communicationtherewith for rotating the spindle motor hub, the stator tooth having atooth body portion attached to the stator rim and a distal shoe adjacentthe magnet, the distal shoe extends vertically beyond the tooth bodyportion in a direction along the axis of rotation, only the at least onereduced height stator tooth being positionable adjacent the head stackassembly for allowing the head stack assembly to pivot over the reducedheight stator tooth.